I have noticed what seems like a bug where the Apple Watch sends an iMessage from the wrong account. It has happened to both my girlfriend and I who both have Apple Watches. We will have an ongoing iMessage conversation on our iPhones and randomly a reply from the watch will sometimes come from a secondary iMessage address such as the iCloud account. This creates a separate conversation on the iPhone. Confirmed "Start new conversations from" are set to our primary phone numbers, and removed the iCloud accounts from Messages settings. I have a secondary (work) phone number associated with Messages also and now it has started randomly sending from that number. Seems to occur under random circumstances, so difficult to reproduce, but happens often enough. Has anyone else noticed this?